Abstract:A basic design method of doubly acting fluid viscous dampers with double guide bars is presented. The flow of the viscoelastic fluid between two parallel plates, one of which is started suddenly and the other of which is still, is analyzed. According to this solution, the velocity and the shear stress of the fluid at the fringe of the piston are solved approximately. A mathematical model of viscous dampers is derived, and the shock test is carried out. From experimental results, the parameters of the mathemati… Show more
“…The influence of initial velocity V 0 on the shock behavior in controlled parameters could be inferred in that the increase of initial velocity would increase the total flow and then affect the shock force according to (17) and (6); the shock force waves were shown in Figure 6 under different initial velocities. In comparison, it was obvious that the shape trend of shock force wave had similar values under different initial velocity V 0 , and the peak value increased with the initial velocity increase, which accorded with the theory analysis as well as the mechanical performances of the shock wave simulator.…”
Section: The Influence Of Initial Velocity V 0 On the Shock Behaviormentioning
confidence: 98%
“…Shams et al analyzed hydraulic shock absorber valve behavior using CFD-FEA [16]. Jiuhong et al presented a design method for fluid viscous dampers, derived mathematical model of viscous dampers, and carried out the shock test [17]. Hou et al proposed a new model for nonlinear viscous fluid dampers with a simple annular orifice and analyzed its fluid dynamics behavior and shear-thinning effects [18][19][20].…”
The simulation of regular shock wave (e.g., half-sine) can be achieved by the traditional rubber shock simulator, but the practical high-power shock wave characterized by steep prepeak and gentle postpeak is hard to be realized by the same. To tackle this disadvantage, a novel high-power hydraulic shock wave simulator based on the live firing muzzle shock principle was proposed in the current work. The influence of the typical shock characteristic parameters on the shock force wave was investigated via both theoretical deduction and software simulation. According to the obtained data compared with the results, in fact, it can be concluded that the developed hydraulic shock wave simulator can be applied to simulate the real condition of the shocking system. Further, the similarity evaluation of shock wave simulation was achieved based on the curvature distance, and the results stated that the simulation method was reasonable and the structural optimization based on software simulation is also beneficial to the increase of efficiency. Finally, the combination of theoretical analysis and simulation for the development of artillery recoil tester is a comprehensive approach in the design and structure optimization of the recoil system.
“…The influence of initial velocity V 0 on the shock behavior in controlled parameters could be inferred in that the increase of initial velocity would increase the total flow and then affect the shock force according to (17) and (6); the shock force waves were shown in Figure 6 under different initial velocities. In comparison, it was obvious that the shape trend of shock force wave had similar values under different initial velocity V 0 , and the peak value increased with the initial velocity increase, which accorded with the theory analysis as well as the mechanical performances of the shock wave simulator.…”
Section: The Influence Of Initial Velocity V 0 On the Shock Behaviormentioning
confidence: 98%
“…Shams et al analyzed hydraulic shock absorber valve behavior using CFD-FEA [16]. Jiuhong et al presented a design method for fluid viscous dampers, derived mathematical model of viscous dampers, and carried out the shock test [17]. Hou et al proposed a new model for nonlinear viscous fluid dampers with a simple annular orifice and analyzed its fluid dynamics behavior and shear-thinning effects [18][19][20].…”
The simulation of regular shock wave (e.g., half-sine) can be achieved by the traditional rubber shock simulator, but the practical high-power shock wave characterized by steep prepeak and gentle postpeak is hard to be realized by the same. To tackle this disadvantage, a novel high-power hydraulic shock wave simulator based on the live firing muzzle shock principle was proposed in the current work. The influence of the typical shock characteristic parameters on the shock force wave was investigated via both theoretical deduction and software simulation. According to the obtained data compared with the results, in fact, it can be concluded that the developed hydraulic shock wave simulator can be applied to simulate the real condition of the shocking system. Further, the similarity evaluation of shock wave simulation was achieved based on the curvature distance, and the results stated that the simulation method was reasonable and the structural optimization based on software simulation is also beneficial to the increase of efficiency. Finally, the combination of theoretical analysis and simulation for the development of artillery recoil tester is a comprehensive approach in the design and structure optimization of the recoil system.
“…For determination of suitability of the damper parameters, the value of damper constant often represents the size of the damper. A higher damper constant increases the size of the piston head and thus the overall size of the damper thereby making these dampers heavier than those with smaller piston head (Hart and Wong, 2000; Rittweger et al., 2002 and Jiuhong et al., 2008). Figure 3.(a) SDOF system with fluid viscous damper, (b) half-cycle sine shock, (c) initial-peak saw tooth shock and (d) rectangular shock.…”
Section: Example Studymentioning
confidence: 99%
“…For determination of suitability of the damper parameters, the value of damper constant often represents the size of the damper. A higher damper constant increases the size of the piston head and thus the overall size of the damper thereby making these dampers heavier than those with smaller piston head (Hart and Wong, 2000;Rittweger et al, 2002 andJiuhong et al, 2008). The above example structure represents a very stiff system (natural frequency equal to 20 Hz), while the ratio of duration of excitation (t d ) to time period (T n ) of the structure satisfies the criterion for impulse type of loading.…”
Energy dissipating damping devices such as fluid viscous dampers (FVDs) often have applications in shock vibration control of structural and mechanical systems. Nonlinear FVDs are more suitable compared to the linear FVDs for applications where large force and velocities are exerted, such as in structures subjected to shock excitations. This paper discusses the influence of shock impulse characteristics on vibration control of a single-degree-of-freedom system with linear and nonlinear fluid viscous dampers for three types of shock excitation profile, viz. half-cycle sine, initial-peak saw tooth and rectangular. The following response parameters have been considered: (1) maximum acceleration of the structure, (2) maximum displacement of the structure, and (3) time required for attenuation of response below a specified threshold. An approximation based on the concept of equal energy dissipation to determine the response of the structure with nonlinear fluid viscous dampers subjected to shock excitation has been proposed. The paper also presents non-dimensional design charts for above shock pulses for linear and nonlinear fluid viscous dampers, which can be used for preliminary decision on damper parameters to be used in design.
“…Hydraulic shock simulator valve behavior was analyzed by Shams M and Ebrahimi R using the method of CFD-FEA [27]. The mathematical model of fluid viscous shock simulator used in the shock test was derived by Jia and Du [28]. Considering a simple annular orifice, a new model for nonlinear viscous fluid dampers used in the shock or damper fields was proposed by Hou C Y and its fluid dynamics behavior and shear-thinning effects were analyzed [29][30][31].…”
For simulating the shock wave with high peak force in a short duration, a novel variable damping hydraulic shock wave simulator was developed, and it was used for simulating the cannon recoil motion. The working principle of this simulator was explained with the assistance of established mathematical model and the flow behavior in damping channel was analyzed. The shock wave characteristics curves were obtained by using the numerical computation method. The results showed that the shock wave characteristics were directly related to the sectional area of the damping channel and the damping fluid medium characteristic; the shock wave curve can be simulated by adjusting the variable damping parameters. The computational results agreed well with the theory analysis, which meant that the proposed mathematical model can be used for supplying theoretical references for the cannon recoil motion in artillery fire shock simulation test.
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